Does anyone know the connector polarity for a Sharp A250 notebook please? I
have been given one without the external power unit and I want to test it
before buying a new PS. The notebook label specifies an EA-J02V 22v 1.8Amp
ac adaptor, that connects with a 3.5/1.35mm connector.

I need to know is the center pin positive or negative to chassis?

TIA
Malcolm L
Somerset UK